This is because butterfly caterpillars are host specific. Plant-wise, the caterpillars of some butterfly species like asters, black-eyed Susan, clover, lupines, milkweed, sedum or violets. Aspen, birch, cherry, hackberry, oak or willow trees make caterpillars of other butterfly species equally happy.
each Br-F bond would be polar or BF4-, there is an extra electron making this a polar molecule. PCl5 has the Cl atoms that must be as far apart from each other as possible and therefore would create equal but opposite pulls.ach Br-F bond would be polar or BF4-, there is an extra electron making this a polar molecule. PCl5 has the Cl atoms that must be as far apart from each other as possible and therefore would create equal but opposite pulls.
A molecule like CH4, (methane), will be nonpolar. All the ligands attached to carbon have the same electronegativity, so there is no difference in dipole around carbon.Another determiner regarding polarity is the presence of lone pairs of electrons. Ammonia (NH3) has ligands that all have the same electronegativity. molecule like CH4, (methane), will be nonpolar. All the ligands attached to carbon have the same electronegativity, so there is no difference in dipole around carbon.